Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward
Number of Options, Outstanding, Beginning balance	1,924
Number of Options, Granted	22
Number of Options, Forfeited	(84)
Number of Options, Outstanding, Ending balance	1,862	1,924
Number of Options, Vested and expected to vest	1,862
Number of Options, Exercisable	1,683
Weighted-Average Exercise Price, Outstanding, Beginning balance	$ 11.93
Weighted-Average Exercise Price, Granted	3.37
Weighted-Average Exercise Price, Forfeited	8.92
Weighted-Average Exercise Price, Outstanding, Ending balance	11.97	$ 11.93
Weighted-Average Exercise Price, Vested and expected to vest	11.97
Weighted-Average Exercise Price, Exercisable	$ 12.69
Weighted-Average Remaining Contractual Term	6 years 14 days	6 years 8 months 15 days
Weighted-Average Remaining Contractual Term, Vested and expected to vest	6 years 14 days
Weighted-Average Remaining Contractual Term, Exercisable	5 years 10 months 2 days
Aggregate Intrinsic Value, Outstanding	$ 1,254	$ 12
Aggregate Intrinsic Value, Vested and expected to vest	1,254
Aggregate Intrinsic Value, Exercisable	$ 848